The present invention relates to a method for quickly detecting and identifying pathogenic bacteria in order to treat an infection (particularly septicemia) at an early stage.
Septicemia is a serious systemic infection. It is indispensable to detect and identify pathogenic bacteria in blood for definite diagnosis of septicemia.
In recent years, the number of serious patients who are likely to develop septicemia has increased with the advancement of medical treatment such as cancer therapy and an organ transplant.
Multi-drug resistant bacteria such as methicillia resistant staphlococcus aureus (MRSA) may cause septicemia from the viewpoint of nosocomial infection. In order to select an appropriate antimicrobial drug to save the life of the patient, it is important to detect and identify pathogenic bacteria in blood as promptly as possible in clinical practice.
However, since the current microbiological detection method takes at least 18 hours to identify bacteria after submission of a blood culture bottle, it is necessary to carry out empirical therapy until the result is obtained. Therefore, the antimicrobial drug has been necessarily selected blindly.
As a result, multi-drug resistant bacteria may emerge due to the use of a broad-spectrum antimicrobial drug, or a situation in which the life of the septic patient cannot be saved due to inappropriate selection of the antimicrobial drug may occur.
A method that amplifies the DNA of pathogenic bacteria responsible for septicemia by polymerase chain reaction (PCR), and hybridizes the amplified DNA of the pathogenic bacteria with a nucleotide probe specific to the target bacterial species empirically determined to detect and identify the pathogenic bacteria has been disclosed (JP-A-6-90799).
Real-time PCR technology has also been developed in order to achieve prompt detection and identification (Journal of Analytical Bio-Science, Vol. 28, No. 5. (2005), pp. 400 to 404).
The basic principle of this septicemia examination method is real-time PCR using a hybridization probe.
However, it is necessary to prepare a hybridization probe specific to each bacterial species when using this method. Therefore, in order to identify a large number of pathogenic bacteria, it is necessary to prepare a large number of hybridization probes.
Specifically, since the number of bacterial species to be detected is determined by the number of probes to be prepared, it is practically impossible to identify a wide range of bacterial species.